Field
The described technology generally relates to an amplifier control apparatus, for example, an apparatus for controlling a pulse width modulation (PWM) amplifier.
Description of the Related Technology
In recent decades, the power electronics industry has witnessed PWM technology become a clear leader over traditional analog design due to its many advantages in terms of physical size, weight, thermal performance, and power efficiency. In contrast with representing signals as continuously varying analog voltages, PWM technology encodes signals as streams of digital pulses. The signal is encoded by changing the width of the pulses over time so that the pulse width (or equivalently, the duty cycle) tracks the signal being encoded.
The main advantage of PWM over analog is that it is much more energy efficient. Power dissipated in any circuit element is substantially equal to the product of current through the element times the voltage across it. In an analog circuit, the transistor conducts current and simultaneously has a voltage across it, and therefore always dissipates significant power. However, in an ideal PWM system, a transistor is either turned off (in which case its current is zero) or it is turned on (hence its voltage drop is zero), and therefore the transistor dissipates no power.